When work is being carried out in a toxic atmosphere, for example an atmosphere which is potentially dangerous due to the presence of poisonous gases or fumes, radioactive dust, asbestos dust or the like, it is conventional practice for personnel entering the dangerous environment to put on a respirator in the form of a face mask fed with clean air through a hose or hoses connected to an air filter unit which is also worn, for example by attachment to a waist belt. On entering and leaving the dangerous area, personnel pass through successive decontamination zones, typically including a cubicle for changing into or out of a transit suit, when leaving on the way to a final decontamination zone at which the respirator is removed, showering is carried out, and a further change of clothes is made. Air pumps or air movers are employed to establish a pressure gradient decreasing from downstream to the upstream working area, to assist confinement of contaminant material to the dangerous area being worked. One problem which arises at the showering stage is that, although the face mask would in theory preferably be left on during initial washing, or possibly removed and separately washed, the filter unit has to be kept dry to avoid clogging of the filter and other possible damage. On the other hand, the contaminated filter unit should not be exposed to the clean environment on the far side of the shower cubicle from the dangerous area. In practice, therefore, the respirator is often removed before entering the shower cubicle, and left there in dirty condition for subsequent use. However, this act of removing the face mask outside the shower can cause scattering of dangerous dust and particulates in an area downstream of the primary decontamination zones.
Other problems can also arise in connection with the theoretically preferred practice of not removing the respirator prior to showering, which is an important requirement not only for safety of the personnel involved, but also for the general purpose of confining contaminant material.
Moreover, further problems can arise in handling the respirator with an unclean filter unit downstream of the shower cubicle, i.e. in the nominally clean environment, particularly in view of the fact firstly that the filter unit usually operates from a rechargeable power supply, and recharging may be required prior to future use, and secondly that the used filter elements may have to be replaced by fresh ones.
It is an object of this invention to provide a solution to the above-described problem.